During the course of a pregnancy, physicians and patients desire as much information as possible regarding the health of the fetus. For both emotional and medical reasons, this information is sought as early in term as possible, and with the fewest possible risks to both mother and child. Although the widely used first trimester chorionic villus sampling (CVS) and second trimester amniocentesis are relatively safe, both procedures are not without negligible risks. In efforts to avoid these risks altogether, researchers have turned toward isolating circulating fetal nucleated red blood cells (FNRBCs) from maternal blood as an alternative, non- invasive source of fetal tissue. Despite the development of FNRBC enrichment methods, there has been limited success with their coupling to subsequent aneuploidy screening and several challenges still must be overcome such as ability to test single fetal cells for 24-chromosome aneuploidy, confirm the isolated cell's origin (fetal versus maternal) and simultaneously screen for diseases caused by single nucleotide variants or micro in/dels. Our innovative Parental SupportTM technology provides a solution to all of these challenges and the development of a first trimester non-invasive prenatal diagnostic test is the ultimate goal of this grant application. In Phase I, we first plan to optimize single cell lysis and whole genome amplification protocols specifically for antibody-stained FNRBCs.. Protocol optimization for single cell analysis falls within the core competencies of GSN as we have previously successfully commercialized an innovative single cell molecular karyotyping protocol to enable genetic analysis of single blastomeres within 24 hours. We will then systematically evaluate which combination of existing FNRBC enrichment methods provides maximum yield and purity suitable for subsequent Parental Support-based genetic analysis using predefined mixtures of fetal and adult blood. The main objective of Phase II will be to transition from the predefined blood mixtures of fetal and adult blood to actual maternal blood samples. We will first conduct a pilot study to determine which of the best FNRBC isolation method(s) identified in Phase I should become the lead method. Using this lead method, we will then conduct a larger study to evaluate concordance between aneuploidy diagnosis by Parental SupportTM and karyotyping by amniocentesis or chorionic villus sampling. If successful, we expect that the completion of these Aims would have a major impact on the field of prenatal diagnosis, improve the lives of millions of couples and children worldwide, and bring non-invasive diagnosis to the mainstream of prenatal medicine. PUBLIC HEALTH RELEVANCE: In the absence of prenatal diagnosis, up to 1 in 50 babies have serious physical or mental handicaps, up to 1 in 30 babies have some form of congenital malformation, and up to 1 in 200 have a phenotypically significant chromosome abnormality Although these abnormalities can be diagnosed with techniques such as amniocentesis or chorionic villus sampling, both procedures carry an increased risk of harm to both the mother and fetus. Our innovative technology has the potential to evaluate the health of an unborn child by simply analyzing the mother's blood, thereby minimizing the risks of the procedure and expanding prenatal screening to the general population.